Throughout my studies for my Master’s in Human Movement, a topic that repeatedly attracted my attention was the important role the gluteals played in foot alignment and foot function. Whether it was the association between hip strength and lower extremity injuries or reported hip weakness after lateral ankle sprain, I saw the applicability of this research for my current patients and clients.
The gluteus medius is a primary hip abductor muscle providing frontal plane stability to the hip and knee during walking, jumping and squatting. This fan-like muscle originates on the ilium between the middle and posterior gluteal lines and attaches on the lateral aspect of the greater trochanter. Although rarely recognized for its subdivisions, anatomical studies have shown this muscle to consist of three very distinct subdivisions – an anterior, middle and posterior. The muscle fibers of the anterior and middle divisions run vertically, making these divisions activated during hip flexion and internal rotation. Conversely, the posterior muscle fibers run more horizontally, making them more effective at hip external rotation and extension.
Weak or underactive gluteus medius has been associated with an increase risk of injury to the lower extremity and with gait abnormalities, such as a Trendelenburg gait. Studies have demonstrated a noted difference in anterior and middle gluteus medius strength when compared to posterior division strength. With the posterior division being responsible for external rotation and frontal plane knee and foot alignment, exercise programs specific to posterior division activation could play an important role in injury prevention and improving lower extremity function.
If you have a client or athlete who you suspect has a hip abductor weakness, and also presents with foot over-pronation, a baseline gluteus medius strength assessment is a must. A gluteus Medius stregnth assessment can be done either non-weight bearing or weight bearing. I prefer to do the gluteus medius assessment standing up as the primary glute activation is during midstance of gait, so this type of strength assessment would be considered more functional.
If you choose a side-lying strength assessment, have the client or athlete lie on their side and slightly flex and internally rotate the hip while performing hip abduction. A score between 3 and 5 is given for abducting against gravity, abduction against gravity plus moderate resistance, and abduction against gravity plus maximum resistance. Repeat the test with the hip in slight extension and external rotation while abducting. Varying the hip flexion and extension will test both the anterior and posterior fibers of the gluteus medius.
To test a client or athlete weight-bearing, there are several tests you can perform including the Trendelenburg test and a single-leg squat test. For the Trendelenburg test have the client stand on one foot. Look at frontal plane pelvis alignment. If you notice a drop in the hip on the contralateral side of the standing leg, that would be a positive Trendelenburg test. For a single-leg squat assessment, have the client or athlete begin in a single leg stance, note the level of the pelvis before initiating the squat. Advise the client or athlete to squat to 45 degree knee bend. Note the frontal knee position. If there is an increase in knee valgus, this would be suggestive of gluteus medius weakness.
When strengthening the gluteus medius, you want to design a fitness program that the research demonstrates has the highest gluteus medius activation. Weight-bearing strengthening exercises have been shown to produce significantly higher gluteus medius activity in comparison to non weight bearing exercises.
Three of the best exercises for strengthening the posterior division of the gluteus medius and concomitantly improving frontal plane knee and foot alignment are the: wall press, pelvis drop and the single leg squat. EMG studies have supported posterior division activation, with the highest activation observed in the wall press exercise.
Have the client stand next to a wall with the right leg further from the wall. Assume a single leg stance position on the right leg with the left knee and hip flexed to 60 degrees. Maintain this position while maximally pushing the left hip, knee and ankle into the wall. Hold 5 seconds and repeat 5 times.
Have the client stand on their right leg on a small step. Allow the left foot to drop below the height of the step, causing the pelvis to drop. Exhale as they bring the foot up to the level of the step and level out the pelvis. Repeat 10 times.
Single Leg Squat
Beginning in a single leg stance, clients are to lower to a 45 degree knee flexion. Hold 5 seconds while trying to maintain frontal plane knee alignment. Repeat 5 times.
With the association of gluteus medius weakness and patellofemoral pain syndrome, ITB syndrome and foot dysfunction, gluteus medius activation should be an integral component to all fitness and strength training programs. For the client with a noted frontal plane imbalance in the knee and foot, gluteus medius activation should be done in conjuction with posterior tibialis strengthening and gastrocsoleus flexibility training.
DiStefano, L. Gluteal muscle activation during common therapeutic exercises. J Ortho & Sports Physical Therapy, 2009. 39(7): 532:540.
O’Sullivan, K. Electromyographic analysis of the three subdivisions of gluteus medius during weight-bearing exercises. Sports Medicine, Arthroscopy, Rehab Therapy and Technology, 2010. 2(17).
This post was originally published on Dr. Emily Splichal's blog for the Evidence Based Fitness Academy.
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